A jury concluded last month that the 2009 firing was in retaliation for the manager's plan to tell regulators about his safety concerns at the adjoining Salem and Hope Creek plants. They are the second-largest nuclear generating facility in the U.S.

The Nuclear Regulatory Commission sent a letter to plant operator PSE&G on Friday asking it to detail what it is doing to ensure the firing doesn't have a chilling effect on other would-be whistleblowers.

PSE&G was not part of the court case because the security manager worked for a contractor. But the NRC says PSE&G is responsible for contractors' actions.